Non-foaming wax



United This invention relates to compositions for controlling foaming of waxes and more particularly for inhibiting foaming of waxes used in coating operations.

As is Well known to those familiar with the art of coating paper with wax, one method in common practice is to dip the paper in a hot molten wax bath whereby the paper is coated with the wax and rendered waterproof. It is also known that in general molten waxes have marked foaming tendencies and as a result foaming problems must be dealt with. When this foam is stable it solidifiies on the surface of the paper with the result that the paper is only partially covered with wax. If a container prepared from such paper is filled with a liquid, the liquid penetrates the paper through the areas which had been covered by the foam thereby weakening the paper container causing bulging and leakers. Furthermore, such a container is unattractive.

It is, therefore, a principal object of the present invention to provide a non-foaming wax. Another object of my invention is to provide a combination of certain esters with an alkali metal fatty acid soap in critical ratios which combination eliminates foaming tendencies of waxes. A further object of the present invention is to provide a non-foaming wax containing a minor amount of this critical combination of additives. Other objects and advantages of the present invention will become apparent as the invention is hereinafter more thoroughly described.

I have found that the foaming tendencies of wax can be sharply reduced economically and simply. This can be accomplished by adding to the wax a minor amount of certain esters and certain fatty acid soaps within a critical range of ratios by weight as an antifoamant. The present invention resides primarily in an antifoamant composition consisting of a major proportion of an ester of a polyhydric alcohol used in combination with a minor proportion of a fatty acid soap which composition is then incorporated in a Wax. Suitable esters are those prepared by reacting a fatty acid such as lauric, myristic, palmitic, stearic, oleic, ricinoleic, and the like, with a polyhydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, glycerine, polyglycols, mannitol, sorbitol, and the like. Typical esters are glycerol monostearate, diglycol monostearate, polyglycol palmitate. Of the many suitable esters available, monoglycerides are preferred. Suitable soaps include potassium and lithium fatty acid soaps. Of these two types of soaps, potassium fatty acid soaps are preferred because they are more effective, cheaper, and available in greater quantities than the corresponding lithium soaps.

As used herein and in the appended claims the term wax includes paraflin wax as that term is commonly understood and in addition the paraffin wax may contain such materials as higher boiling distillate waxes, microcrystalline wax, polyethylenes, and perhaps other additives. In general, the term paraffin wax is used to define the hard, crystalline Wax commonly obtained from petroleum distillates, derived from mineral oils of the mixed base or parafiin base type. By the present refining methods, crude petroleum oil is subjected to distillation whereby it is separated into a series of fractions known as paraflin distillates. The wax is separated from the parafiin distillate by chilling and filtering or.

Patent Patented June 18, 1957 by the use of a solvent, as for example, propane or a. ketone such as methyl ethyl ketone. The wax obtained by either of these two methods contains from 10 to 50 percent oil and is generally referred to as slack wax.

This slack wax is subjected to a sweating operationto remove the oil. The resulting wax usually contains 3 to 6 percent oil, but by proper sweating the oil content may be reduced to less than 1 percent. Also, the oil content may be reduced to an acceptable value by other methods such as solvent de-oiling or press de-oiling. The final product is kown as refined wax or paraffin wax and is graded according the tensile strength, meltin g point, oil content, hardness, etc.

The quantity of the antifoamant compositon added to the wax will depend upon a number of factors. Thus, the exact quantity of the antifoamant added will depend upon the particular ester and fatty acid soap and the relative quantities of each making up the antifoamant. In general, the antifoamant may be employed to advantage in wax in amounts ranging from about 0.03 to about 0.3 percent by weight, of the wax composition. Quantities less than 0.03 percent are insufficient to reduce the foaming characteristics of the wax and if the amount is in excess of 0.3 percent the result is unsatisfactory. A preferred range is from about 0.1 to about 0.2 percent by weight of the wax compositon. Suitable quantities of the fatty acid soap in comparison to the amount of ester ranges:

from about 3 to 10 percent of the former with the re-- mainder of the antifoamant being made up of the ester. I prefer, however, to use about 5 to 7 percent of the soap and from to 93 percent of the ester as the antifoam ant composition.

While I do not wish to be bound by any theory asuto how my results are produced, I believe that the correct explanation of these results is substantially as follows: The ester acts as a coupling agent and hereinafter will be identified as a coupling agent which affects the mutual limited solubility between the soap and wax that is required to inhibit foam formation.

The relative effectiveness of the various soap-coupling agent combinations of my invention in preventing foam formation in a Wax may be demonstrated by means of the following foam tests. Briefly, the foam test consists of introducing a stream of air at a fixed rate into a measured quantity of wax at F. by means of a fritted glass gas dispersion tube. After a predetermined time the volume of foam produced is measured as well as the time required for the bulk of the foam to dissipate after the air flow is stopped. This method is a modification of A. S.'T. M. method D 892-46T. The base waxes A, B, C, and D used in the examples are basically of the same composition, the melting points of which are 126.6, 125, 125.5 and 126.9 F. respectively as determined by the A. S. T. M. melting point method. They differ only in their foaming tendencies.

In the following specific examples, there by means of this foaming test the advantageous results obtained by incorporating in a wax the antifoamants of my invention.

Mixture of 5 parts of potassium laurate with 95'parts of glyceryl monolaurate.

are illustrated Several other waxes have been tested in a similar manner, both alone and with the antifoamant and have shown the same foam reduction as indicated in the foregoing example. In addition to this laboratory data, several commercial machine coating experiments have been conducted and a very decided reduction or elimination of 'foam on the coated paper was observed.

Example 2 demonstrates that the components of the anti-foamant, potassium laurate and glyceryl monolaurate,

1 Difficultly soluble in wax.

The range of effective foam suppression of a mixture of 6 7 percent potassium laurate with 94-93 percent glyceryl monolaurate is illustrated by the data in Table I.

Table I Foam Vol. in Time in m1. Sec.

Wax B (control) 24.0 8. 7 100 parts Wax B, 0.02 part antifoamant. 22.0 10.3 100 parts Wax B, 0.03 part antiioamant- 21.0 10.2 100 parts Wax B, 0.04 part antifoamant. 3. 5 3. 7 100 parts Wax B, 0.05 part antifoamant.- 1.0 1.0 Wax A (control) 21. 5 10.3 100 parts Wax A, 0.1 part antifoamant 2.0 1. 0 100 parts Wax A, 0.2 part antifoamant 2. 0 1.0 100 parts Wax A, 0.3 part antiioamant 4. 0 12.8

In order to demonstrate that a proper combination of soap and coupling agent is required to inhibit foam efiectively in a wax, the following data are presented.

[Antiioamant composition: 15% potasslium lam-ate; 85% glyceryl monolaurate.

Foam

Vol. in Time in ml. Sec.

Wax B (control) 24. 0 8. 7 100 parts Wax B, 0.01 part antifoamant 25. 0 10. 4 100 parts Wax B, 0.05 part antifoamant 27. 0 12. 4 100 parts Wax B, 0.1 part antifoamant 26.0 10.2

2,795,355 I p n p p [Antifoamant composition: 3% potassium laurate; 97% glyceryl monolaurata] Foam Vol. in Time in mi. See.

Wax B (control) 24.0 8.7 100 parts Wax B, 0.05 part antifoamant. 25. 5 12.7 100 parts Wax B, 0.1 part antifoamant 3. 0 3. 3 100 parts Wax B, 0.2 part antifoamant 1. 5 2. 6

[Antitoamant composition: 2% potaZsSiJum laurate; 98% glyceryl monolaur e.

Foam

Vol. in Time in mi. See.

Wax B (control) 24. 0 8. 7 100 parts Wax B, 0.1 part antifoamant 22.5 11. 2 100 parts Wax B, 0.2 part antifoamant 25. 5 13. 8 100 parts Wax B, 0.3 part antifoamant 25. 0 12.1

[Antifoamant composition: 1% potassium laurate; 99% glyceryl monolaurate] Foam Vol. in Time in Jul. Sec.

Wax B (control) 24. 0 8. 7 26. 5 11.8 25. 5 14. 1 100 parts Wax B, 0.3 part antitoamant 24. 5 9. 3 100 parts Wax B, 0.4 part antifoamant 26. 5 14. 3

As is apparent from the data of Example 3 below my antifoamant compositions are eiiective in inhibiting the foaming of wax mixtures. This is highly desirable because as is well known that in a blend of two or more waxes the foaming tendencies of the resulting blend increases as the amount of higher melting point wax in the blend increases.

1 5 parts potassium Iaurate and parts glyceryl monolaurate.

Table 1 1. illustrates that other esters maybe used in this invention. It also includes data showing that lithium soap is effective but that soaps composed of fatty acids of sodium, calcium, and aluminum have no foam suppressing properties when used in combination with various esters. The datav of Table II were obtained by adding 0.1 part of the :antifoa-mant to parts of wax wherein the ntifoamant consistedof 5% soap.and95%;of-the.cou ling agent.

Table II mmum dllaurate. None Aluminum stearate.

Antiioamant Composition Foam Wax Soap Coupling Agent Vol., Time,

ml. Sec.

None None 32.0 14.0 Lithium laurate Glyceryl monolaurate. 20.0 6.6 Potassiummyristate do 1. 5 1. 5 None None 23.5 8.0 D Potassiummyristate. Glycerylmonostearate- 8.5 3.2 D do Glyceryl monopleate- 31.0 12.4 C None 32.0 14.0 C Glyceryl monolaurate. 9. 4. 9 D None None 23.5 8.0 D. Potassium laurate.. Glycerylmonolaurate. 1.0 1.0 D do -d 1.0 1.0 D -do Glycerylmonostearete. 1.0 1.0 D do Glyceryl mono-oleate. 4.0 3.6 O None None 32.0 14.0 0 Potasslumlaurate... Hyidrogenated Castor 26.5 8.3

o 0 do Hydrogenated lard 25.0 7.4 0 do Hydrogenated flsh oil. 27. 0 8. 4 0 do Hydrogenated tallow. 23.0 7.2 D None None 23.5 8.0 D Potassium laurate-.- Polyethylene glycol 14.0 5.4

s eara D .do Ethylene glycol 16.0 6.7

stearate. D None None 23.5 8.0 D Potassiumpalmitate. Glycerylmonolaurate. 2.0 1.0 D Glycerylmonostearate. 15.0 3.5 D Glyeeryl mono-oleate 15. 0 6. 4 D None None 23.5 8.0 D Potassium stearate. Glycerylmonolaurate. 24.0 8.1 D do Glycerylmonostearate. 23.0 6.8 D.. do Glyoeryl mono-oleate. 15.0 6.0 O Nnne None 32.0 14.0 0 Potassium oleatem. Glyceryl monolaurate. 6.0 4.0 None None 32.0 14.0 Sodium myristate Glyceryl mono1aurate 35.0 14.5 Nonem; 23.5 8.0 Glyeeryl monolaurate. 24. 0 8. 4 do Glycerylmonostearate. 23.5 11.6 N N one 32. 0 14. 0 Sodium laurate Glycerylmonolaurate. 36.0 12.3 None None 32.0 14.0 Sodium palmitate..- Glycerylmonolaurata 33.5 12.1 Sodium stearate... Glycerylmonostearate. 30.5 10.0 d do 42.0 13. 5 None 32.0 14.0 Glyoeryl monolaurate. 34. 0 19. 0 -do 29.0 13.5 Ether washed aludo 28.0 9.1

None Glycerylmonostearate.

Methods for preparing the soaps and the esters used in this invention are well known to those skilled in the art. One such method is substantially as follows: The fatty acid is mixed with glycerine, potassium hydroxide added after which the mixture is heated until esterification is accomplished. In this process the potassium soap of the corresponding fatty acid is also produced.

Commercial mono glycerides containing di and triglycerides are satisfactory for use in this invention. For example, when coconut oil which is a mixture of triglycerides of several fatty acids is used it is desirable to add excess glycerine with a suitable catalyst such as potassium hydroxide then heat the mixture in order to produce the self emulsifying grade of monoglycericles. Such a product will contain mixtures of monoglycerides and potassium soaps as well as some di, and triglycerides.

While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

l. A substantially anhydrous wax composition of improved antifoaming properties intended to be used in the molten state consisting essentially of a paraifin wax and from about .03 to .3 part of an antifoamant composition per 100 parts of said wax wherein said antifoamant comprises an ester formed by reacting a fatty acid containing 11 to 20 carbon atoms with a polyhydric alcohol containing 2 to 18 carbon atoms and an alkali metal fatty acid soap wherein the alkali metal is selected from the group consisting of potassium and lithium wherein the relative proportion of said ester and said alkali metal fatty acid soap in said antifoamant composition varies from to 97 percent and 10 to 3 percent respectively.

2. A substantially anhydrous wax composition of improved antifoaming properties intended to be used in the molten state consisting of .l to .2 part of an antifoamant composition per 100 parts of a parafiin wax wherein said antifoamant comprises an ester formed by reacting a fatty acid containing 11 to 20 carbon atoms with a polyhydric alcohol containing 2 to 18 carbon atoms and an alkali metal fatty acid soap wherein the alkali metal is selected from the group consisting of potassium and lithium wherein the relative proportions of said ester and said alkali metal fatty acid soap in said antifoamant composition vary from 93 to 95 percent and 7 to 5 percent respectively.

3. The product of claim 1 wherein the ester is a monoglycerine.

4. The product of claim 1 wherein the ester is glyceryl monolaurate.

5. The product of claim 1 wherein the alkali metal fatty acid soap is potassium laurate.

6. The product of claim 1 wherein the alkali metal fatty acid soap is potassium myristate.

7. The product of claim 1 wherein the alkali metal fatty acid soap is potassium palmitate.

8. The product of claim 1 wherein the alkali metal fatty acid soap is lithium laurate.

References Cited in the file of this patent UNITED STATES PATENTS 2,346,928 Lightpipe Apr. 18, 1944 2,390,212 Fritz Dec. 4, 1945 2,577,643 Young et al. Dec. 4, 1951 2,658,004 Eldridge et al. Nov. 3, 1953 2,668,150 Luvise Feb. 2, 1954 

1. A SUBSTANTIALLY ANHYDROUS WAX COMPOSITION OF IMPROVED ANTIFOAMING PROPERTIES INTENDED TO BE USED IN THE MOLTEN STATE CONSISTING ESSENTIALLY OF A PARAFFIN WAX AND FROM ABOUT .03 TO .3 PART OF AN ANTIOFORMANT COMPOSITION PER 100 PARTS OF SAID WAX WHEREIN SAID ANTIFOAMANT COMPRISES AN ESTER FORMED BY REACTING A FATTY ACID CONTAINING 11 TO 20 CARBON ATOMS WITH A POLYHYDRIC ALCOHOL CONTAINING 2 TO 18 CARBON ATOMS AND AN ALKALI METAL FATTY ACID SOAP WHEREIN THE ALKALI METAL IS SELECTED FROM THE GROUP CONSISTING OF POTASSIUM AND LITHIUM WHEREIN THE RELATIVE PROPORTION OF SAID ESTER AND SAID ALKALI METAL FATTY ACID SOAP IN SAID ANTIFOAMANT COMPOSITION VARIES FROM 90 TO 97 PERCENT AND 10 TO 3 PERCENT RESPECTIVELY. 